Improve Filter Value Lookups

[d3an]

The FilterValueLookup covers all 70 filter types and their corresponding values. The dictionary needs to be fixed up so that each value perfectly mirrors that provided on the site. Once this step is completed, shortcuts should be added as well. Consider the Market Cap filter. A possible shortcut for Mega ($200bln and more) could just be mega.

As a bonus task, consider adding support for approximate string matching. Take a look at the Levenshtein distance metric and see how others have implemented this technique in their projects.